#include <bits/stdc++.h>

using namespace std;
#define int long long


void solve()
{
    int n; cin >> n;
    string s; cin >> s;
    int ans = 0;
    for(int i = 0;i < n - 1;i ++)
    {
        if(s[i] != s[i + 1]) ans ++;
    }
    if(s[0] == '1') ans ++;
    cout << ans << endl;

}
signed main()
{
    int t; cin >> t;
    while(t--)
    {
        solve();
    }
    return 0;
}